Excerpted from wikipedia...
In 1927, Mary Lou Williams married saxophonist John Williams. She met him at a performance in Cleveland where he was leading his group, the Syncopators, and moved with him to Memphis, Tennessee. He assembled a band in Memphis, which included Mary Lou on piano. In 1929, he accepted an invitation to join Andy Kirk's band in Oklahoma City, leaving 19-year-old Mary Lou to head the Memphis band for its remaining tour dates. Williams eventually joined her husband in Oklahoma City but did not play with the band. The group, now known as Andy Kirk's Twelve Clouds of Joy, relocated to Tulsa, Oklahoma, where Williams spent her free time transporting bodies for an undertaker. When the Clouds of Joy accepted a longstanding engagement in Kansas City, Missouri, Williams joined her husband there and began sitting in with the band, as well as serving as its arranger and composer. She provided Kirk with such songs as Walkin' and Swingin', Twinklin', Cloudy', Little Joe from Chicago and others.
From the first sides Kirk made in Kansas City, Williams was on board as pianist and arranger. (Six sides were recorded in Kansas City during 1929 and remaining 17 sides were recorded in Chicago in 1930, and a further two were recorded in New York in 1930.) During one of those trips to Chicago in 1930, Williams recorded Drag 'Em and Night Life as piano solos. Williams took the name "Mary Lou" at the suggestion of Brunswick's Jack Kapp. The record sold briskly, raising Williams to national prominence. Soon after the recording session she signed on as Kirk's permanent second pianist, playing solo gigs and working as a freelance arranger for such noteworthy names as Earl Hines, Benny Goodman and Tommy Dorsey. In 1937, she produced In the Groove (Brunswick), a collaboration with Dick Wilson, and Benny Goodman asked Mary to write a blues for his band. The result was Roll 'Em, a boogie-woogie piece based on the blues, which followed her successful Camel Hop, Goodman's theme song for his radio show sponsored by Camel cigarettes. Goodman tried to put Williams under contract to write for him exclusively, but she refused, preferring to freelance instead.
Andy Kirk bsx, bb, dir / Edgar Battle, Harry Lawson t / Allen Durham tb / John Harrington cl, as / John Williams as, bar / Lawrence 'Slim' Freeman ts / Claude Williams vn / Mary Lou Williams p, a / William Dirvin bj, g / Edward McNeil d.
Recorded in Chicago on April 30, 1930.
Recorded in Chicago on December 15, 1930.